Checked the code at
http://code.haskell.org/gtk2hs/glib/System/Glib/hsgclosure.c and it is
obviously fixed. I don't know why it didn't work from the community or
ghc74 repositories (maybe I did a mistake somewhere).
I will try to fetch the source for haskell-glib with abs from [ghc74]
when I get home to see if it has the correct (?) code or the faulty
one. Still it is (was yesterday) faulty in [community]. I'll check
that again and provide a bug report if necessary.
cheers
/Johan